Blender export to Unity
Exporting from Cycles to FBX is somewhat fiddly at the moment still. 
As far as i'm aware the exporter reads only trough a principled node - and then not all slots.
I found this Method to somewhat work, its essentially the same as it has been with the old Blender render:

1. For the images to be packed into the .fbx there are two important parts, first you need to connect them to certein inputs of a principled bsdf node. Sadly not all work tough (at least for me atm) i expected the normal input to also work, but it didn't.
 

2. When exporting to .fbx theres two settings you need to change:

 

You need to change "Path Mode" to "Copy" and hit the small icon behind it, i'm currently on 2.8 but the method should apply to 2.79

After that, you can try to reimport the texture into Blender, your Textures should show up in the image/UV Editor.